Safco Products 5144 Task Master Adjustable T-Pad Armrest Set for use with Task Master Chairs, sold separately, Black Optional T-Pad style arm rest Adjustable height 8 1/2 to 11 1/2"H T-Pad armrest set For use with Safco Products Apprentice II 7083BL and 7084BL, Trenton 3420, Precision 3401, 3380BL, 3390BL and Office Stool 5100, sold separately For use with Safco Products Task Master Chair Models 5110, 5113, 5117 and 5120, sold separately Easy installation